Cattle guards or stock guards have long been known. A cattle guard is a device that impedes or deters the passage of livestock, while enabling the passage of vehicles. Cattle guards are typically located where fence lines cross roads, and allow for stock to be confined to defined ranges without the necessity of locating a gate where a roadway crosses a fence line.
Conventionally, cattle guards are provided as an array of mutually parallel spaced apart linear members arranged transverse to the direction of traffic flow. The spacing between the members is chosen to define inter-member spaces that exceed the maximum dimension of the hoof of an animal. Conventionally, this array of mutually parallel spaced apart linear members is placed above an excavation or vault, which defines a space below the local grade level. An animal, typically a cow, upon encountering a cattle guard, will refuse to cross for fear of placing its hoof into the deep hole defined by the inter-member spacing and the ditch below.
Conventionally, cattle guards are formed of linear members having rectangular or triangular cross section, typically fabricated from tubular steel. These linear members are affixed to a plurality of cross members, which themselves are mutually parallel, and which are bolted or set upon a ledge defined by the concrete structure that defines the vault or ditch. For certain conventional cattle guards, triangular or rectangular wings are provided at either end of the linear member array, which bridge the distance between the cattle guard and nearby fence posts. In certain conventional designs, these wings may be hinged.
Conventional cattle guards have a variety of disadvantages. While effective for domesticated cattle, stock guards will oftentimes not deter other kinds of animals. In particular, bison and horses, of both the domesticated and wild varieties, are oftentimes not deterred by conventional stock guards. Additionally, some cattle will still attempt to cross conventional stock guards. Because, the spaces between adjacent linear members in conventional stock guards exceeds the size of an animal's hoof, when an animal attempts to cross a conventional stock guard, injury, typically a broken leg, and death is often the result. Additionally, injury can result when an animal does not notice that the conventional cattle guard is there, for example, when it is hidden by brush, snow or other debris.
Methods have been suggested to provide a safer alternative to conventional stock guards. The “universal cattle guard” available from Outlaw Industrial, LLC of Globe Arizona uses a plurality of mutually parallel spaced about members having a circular cross section, which is placed at grade, i.e., not above an excavated ditch or vault. While the “universal cattle guard” appears to prevent animal injury, its effectiveness as an animal deterrent is suspect for a variety of reasons. For example, because of its open design, debris may accumulate between the tubular members from the bottom (e.g., as a result of water running past the structure), thereby filling up the voids between the adjacent tubular members. Additionally, even when this device is clear of debris, animals can see the natural surface of the ground between the tubular members, which decreases the device's effectiveness.
What is needed is a stock guard that prevents injury, but that is as effective as a deterrent as conventional stock guards.